Risks

Chemotherapy's side effects are different for everyone, due to differences among drugs and dosages and to the body's unique reaction to these medicines. Most side effects are temporary and subside once treatment is finished. But in some cases, chemotherapy can have long-term or even permanent effects.

Short-term side effects

In the process of killing cancer cells, chemotherapy drugs can also damage other rapidly dividing healthy cells, such as those in the hair follicles, bone marrow and digestive tract. The results may include:

Hair loss

Loss of appetite

Nausea and vomiting

Diarrhea

Mouth sores

Fatigue (due to fewer red blood cells)

Increased risk of bruising or bleeding (due to fewer blood platelet cells that help blood clot)

There are drugs to help reduce nausea and vomiting caused by chemotherapy. Also, doctors can sometimes adjust the dose or schedule of the chemotherapy drugs to minimize side effects.

If chemotherapy damages your infection-fighting blood cells, a doctor may adjust your doses of chemotherapy or add medications that help your bone marrow to recover more quickly. Most side effects don't last long.

Long-term side effects

Infertility. One possible side effect that may not go away is infertility. Some anti-cancer drugs damage ovaries.

This may cause menopause symptoms, such as hot flashes and vaginal dryness. Menstrual periods may become irregular or stop (amenorrhea). If ovulation ceases, pregnancy becomes impossible.

If you continue to menstruate, you may still be able to get pregnant, even during treatment. But because the effects of chemotherapy are dangerous to the fetus, talk with your doctor about birth control options before treatment begins.

Nerve damage (neuropathy). Several chemotherapy drugs can affect nerve endings in your hands and feet, leading to numbness, pain, burning or tingling, sensitivity to cold or heat, or weakness in your extremities. These side effects often go away after treatment is finished, but in some cases, they may be long lasting.

Osteoporosis. Women who experience menopause early because of chemotherapy may have a higher risk of the bone-thinning condition osteoporosis. It's generally recommended that these women have periodic bone density tests and, possibly, treatments to prevent bone loss.

Cognitive function. "Chemo brain," "chemo fog" and "chemo memory" are terms used to describe little-understood short-term memory and concentration problems that may occur after chemotherapy. In most cases, these problems go away within a few years.

Heart damage. When used for a long time and in high doses, some drugs — such as epirubicin (Ellence), trastuzumab (Herceptin) and others — can cause permanent heart damage.

Leukemia. Rarely, chemotherapy for breast cancer triggers a secondary cancer, such as cancer of the blood cells (leukemia).

Other side effects

Feelings of fear, sadness and isolation can compound the physical side effects of chemotherapy, both during and after treatment. In fact, some women are unexpectedly sad at the conclusion of treatment.

During chemotherapy, women with breast cancer have regular contact with and support from oncologists and nurses. Everyone involved is working toward the same goal — completion of treatment with the best possible outcome. When it's over, some women feel as if they're alone, with no one to help them return to normal life or deal with fears of breast cancer recurrence.

It may help to talk with someone who has been in the same situation. Connect with others via a cancer-survivor hot line, support group or online community.

Chemotherapy principles: An in-depth discussion of the techniques and its role in treatment. American Cancer Society. http://www.cancer.org/treatment/treatmentsandsideeffects/treatmenttypes/chemotherapy/index. Accessed Aug. 21, 2013.

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